Tufting system

ABSTRACT

A tufting needle (100) comprises a shaft (101) having a tapered formation (103) configured to penetrate and open a passage (105) in a resilient backing material (107). The needle (100) further comprises a filament lumen (109) that leads to an opening (117) proximal to the tapered formation (103), to guide a filament (111) through the passage (105) to create a tuft (113) at the resilient backing material (107). A cutting edge (115) is located at the opening (117) of the filament lumen (109) to cut the filament (111).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Australian Provisional Patent Application No. 2019904414 filed on 22 Nov. 2019, the contents of which are incorporated herein by reference in their entirety.

BACKGROUND Technical Field

The present disclosure relates to tufting, and more specifically to tufting needles and tufting guns including constituent components.

Description of the Related Art

The simplest tool for hand tufting is a narrow, thin walled, hollow cylindrical tube acting as a needle. One end of the needle is beveled to form a needle point and yarn is fed through the other open end. This needle penetrates a backing material to create a hole. The inner edge of the needle, opposite the point, pulls yarn through the hole as the needle is inserted. When the needle is withdrawn, a loop tuft is formed. The needle is then rotated so the needle point is facing in the direction of to the next insertion point. It is moved to that point and inserted to create another loop tuft. The height of the loop tuft is determined by how far the needle is pushed through the backing. The weight of this tufting tool is around 50 grams.

Around 1957, Tai Ping Carpets introduced an electro-mechanical hand tufting gun which was a needle and blade tufting mechanism powered by an electric hand drill. Crank/connecting rod/slider mechanisms, powered by the drill motor, were used to separately reciprocate the needle and the blade. The gun contained a yarn brake which, when combined with a scissor mechanism attached to the blade, enabled tufting of cut pile. An improvement of the tufting gun used a blade containing a sharp V to replace the scissors. Another later improvement was the addition of a hand lever driven rotating presser foot. Yet another improvement was powering a feed roller by the motor to feed yarn into the tufting gun. Electro-mechanical hand tufting guns increase hand tufting productivity by a factor 4 to 5. A disadvantage is the weight of the tufting gun, between 2 to 3 kilograms, which makes their use physically demanding. Another disadvantage is that changing pile type and pile heights is time consuming and quite complex mechanical adjustments.

Electro-pneumatic hand tufting guns were mentioned in Patent Application DE2815801 A1 (Hartleb), published 18 Oct. 1979, U.S. Pat. No. 4,388,881 A (Price), published 21 Jun. 1983, and German patent DE 2621360 C2 (Verzicht), published 6 Dec. 1984. Hofmann Handtuft-Technik GmbH in Germany was producing electro-pneumatic tufting guns prior to 1983. Pneumatic tufting guns, powered by an electric motor, use a jet of compressed air, instead of a yarn blade, to insert yarn, through the needle, into the backing. The needle is reciprocated by a crank/connecting rod/slider mechanism. Cut pile is produced by a rotating a blade, powered by the electric motor, laterally across the face of the tufting needle to cut the yarn. Electro-pneumatic hand tufting guns increase hand tufting productivity by a factor of 6 to 7 times. A disadvantage is the weight of the tufting gun, between 4 to 6 kilograms, which makes their use even more physically demanding than electro-mechanical tufting guns. Manufacturers recommend use of a counter balance to support the gun during tufting. Another disadvantage is that changing pile type and pile heights requires spare parts and is time consuming and mechanically quite complex.

Whereas tufting guns mechanized hand tufting, automation of hand tufting was disclosed by U.S. Pat. No. 5,503,092 (Aubourg, Pongrass, Wilson) in 1996. The method and system of automated tufting has since become known as “robot tufting”. A tufting robot consists of a computer controlled tufting gun mounted on a computer controlled co-ordinate movement system operating under the control of a CAM tufting system. The computer controlled tufting gun mounted on a carriage of the movement system has become known as a “tufting head.” Further improvements to tufting guns employed as tufting heads were in disclosed in a number of subsequent patents. U.S. Pat. No. 5,829,372 (Aubourg, Pongrass, Wilson) disclosed a rotating tufting head where the reciprocating mechanism remained stationary. U.S. Pat. No. 7,218,987 B2 (Mile, Wilson) disclosed a method of controlling a tufting head to selectively tuft cut pile or loop pile, known “cut/loop tufting.” U.S. Pat. No. 8,225,727 B2 (Wilson, Mile, Van Woerkom) discloses a method of controlling a tufting head to selectively vary the tuft pile height, known as “3D tufting.” The combination of this feature with U.S. Pat. No. 7,218,987 B2 is known as “3D cut/loop tufting.” Tufting robots have increased the overall productivity of hand tufting by a factor greater than 40 times.

BRIEF SUMMARY

Despite hand guns significantly increasing the productivity of hand tufting, they have not been economically successful in displacing manual tufting. Despite tufting robots automating hand tufting they have not been economically successful in displacing either manual or tufting gun hand tufting. The economic success of both hand guns and tufting robots is contingent on overcoming the following technical and economic problems:

a. reducing the size, weight and cost of tufting guns

b. making tufting guns less complex, more versatile and easier to use

c. increasing the tufting quality and performance of tufting guns

In light of the shortcomings of known tufting devices, the present disclosure provides improvements in tufting technology that may ameliorate one or more of the problems discussed above.

There is provided a tufting needle (100) comprising:

a shaft (101) having:

-   -   a tapered formation (103) configured to penetrate and open a         passage (105) in a resilient backing material (107);     -   a filament lumen (109), that leads to an opening (117) proximal         to the tapered formation (103), to guide a filament (111)         through the passage (105) to create a tuft (113) at the         resilient backing material (107); and     -   a cutting edge (115) located at the opening (117) of the         filament lumen (109) to cut the filament (111).

The shaft (101) may include a shaft axis (125), wherein the shaft (101) extends from a first end (123) proximal to the tapered formation (103) to an opposite second end (127), and at least a portion of the filament lumen (109) is coaxial with the shaft axis (125).

The tapered formation (103) may comprise a bevel surface (119) leading from a needle point (121) at the first end (123) of the shaft (101).

The cutting edge (115) may be, relative to other portions (131) of the opening (117), axially distal from the first end (123), wherein the cutting edge (115) is directed to cut by axial movement of the tufting needle (100) along the shaft axis (125) towards the first end (123).

The opening (117) may comprise guide portions (129) configured to guide the filament (111) to the cutting edge (115).

At least part of the guide portions (129) may be substantially V shaped to channel the filament (111) to the cutting edge (115).

At least part of the guide portions (129) may be substantially U shaped to channel the filament (111) to the cutting edge (115).

At least part of the guide portions (129) may include at least part of the cutting edge (115).

The shaft (101) may further comprise one or more engagement surfaces (133) to engage with a rotating actuator (134).

The engagement surfaces (133) may include first engagement surfaces (135) as part of a key system (137), wherein the key system (137) rotates the tufting needle (100) with corresponding rotation of the rotating actuator (134).

The key system (137) may be an axially slidable key to enable, at least in part, the tufting needle (100) to move axially along the shaft axis (125).

The first engagement surfaces (135) may be one or more planar surfaces proximal to the second end (127) of the shaft and parallel to the shaft axis (125).

The engagement surfaces (133) may include a second engagement surface (138) as part of a reciprocating system (139), wherein the reciprocating system (139) selectively moves the tufting needle (100) along the shaft axis (125).

The second engagement surface (138) may be formed from one or more collars (141) or grooves (143) on the shaft (101).

The second engagement surface (138) may be rotatably captured by the reciprocating system (139).

The backing material may be a woven fabric.

The filament may be yarn.

There is also provided a needle rotator (134) comprising an electric motor having a hollow motor shaft configured to receive and rotate a corresponding needle shaft.

The hollow motor shaft (134) may comprise engagement surfaces (145) to engage with the needle (100).

The engagement surfaces (145) may be part of an axially slidable key system (137) to allow the needle to move axially in the motor shaft (134).

The engagement surfaces (145) may be planar surfaces parallel to the motor shaft (134) axis.

The needle rotator may comprise a pressing formation (147) on a distal end of the hollow motor shaft.

The pressing formation (147) may comprise a high friction surface (149) for engaging a filament (111) and a backing material (107).

The needle rotator may comprise a pressure sensor to measure a pressure between the pressing formation and a backing material.

There is also provided a linear actuator (139) comprising a stator (14) and a moving core (157) wherein the moving core comprises an aperture (159) to rotatably capture, by a second engagement surface (138), a tufting needle described above.

The second engagement surface (138) may be formed from one or more collars (141) or grooves (143) on the shaft (101) of the needle.

There is provided a tufting gun comprising:

a filament port to introduce a filament into the tufting gun; and

a convergent and divergent jet nozzle formed symmetrically about the filament port and configured to generate a supersonic stream of compressed gas to entrain the filament to a tufting needle.

The tufting gun may further comprise the needle rotator described above.

The tufting needle of the tufting gun may be the tufting needle described above.

The tufting gun may further comprise the linear actuator described above.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A, 1B, and 1C illustrate a tufting needle in profile and in cross section.

FIGS. 2A and 2B illustrate a backing material and a tufting needle in operation forming a tuft.

FIG. 3 is a cross-sectional view of electro-mechanical tufting gun with tufting needle extended and retracted.

FIG. 4A illustrates a tufting gun with an air jet feed.

FIG. 4B illustrates a tufting gun with an air jet feed.

FIG. 4C is a cross-sectional view of an air jet.

FIG. 5 is a cross-sectional view of a hollow motor shaft.

FIG. 6 is a cross-sectional view of an electro-mechanical tufting gun with pneumatic assist.

DETAILED DESCRIPTION

Tufting is a type of weaving in which a filament is inserted through a backing material to form a tuft. For example, in the process of producing chenille fabric or carpet making, yarn is inserted through a backing material to form tufts. The process is however, applicable to filamentary materials other than yarn depending on the intended purpose.

Tufting Needle

Current electro-mechanical tufting guns reciprocate two components to form a tuft in a backing material—a tufting needle and a separate yarn blade. The needle opens a hole in the backing and the blade inserts yarn through the hole into the backing. The blade travels along the inside of the needle, carrying yarn towards and through the hole. To accommodate the blade, the needle is shaped as an open C, circular with an opening and a flat surface along which the blade slides. The blade has a flat V groove to capture the yarn and drag it along needle flat surface. Yarn capture using this method is not totally reliable and can lead to poor tuft quality. Furthermore, this mechanism requires that the inside diameter of the needle must be large enough to internally contain the moving blade which requires an increased penetration force to be applied to the needle. In addition, separate mechanisms are required for reciprocating the needle and the blade as they are reciprocated separately in an out-of-phase manner.

The present disclosure relates to a tufting needle having a cutting blade and devices for actuating the tufting needle.

FIG. 1A illustrates a tufting needle 100 comprising a shaft 101 while FIG. 1B illustrates a cross section of needle 100 in an orientation which is rotated relative to the orientation of FIG. 1A. At a first end 123, shaft 101 has a tapered formation 103 configured to penetrate and open a passage 105 in a resilient backing material 107, shown in FIG. 2A. A filament 111 is guided through passage 105 by a filament lumen 109 that leads to an opening 117 proximal to the tapered formation 103. Filament 111 is guided through the passage 105 to create a tuft 113 at the resilient backing material 107 as shown in FIG. 2A. A cutting edge 115 located at the opening 117 of the filament lumen 109 is configured to cut the filament 111 when sufficient tension is placed on filament 111.

The embodiment provides a simpler, lighter, more effective and less expensive means of mechanical tufting with the added simplification and cost reduction of a single reciprocation mechanism. Further, it reduces the power required to reciprocate the needle.

FIG. 2B illustrates tufting needle 100 in operation, engaging/penetrating a resilient backing material 107 to create tufts 113. Needle 100 moves axially through backing material 107, using tapered formation 103 to penetrate it and create passage 105. Filament 111, passing through filament lumen 109, is guided through passage 105 in the backing material 107. A tuft 113′ is formed in filament 111 over opening 117 of filament lumen 109. The height of tuft 113′ is determined by a tufting stroke length of needle 100, which is the distance that cutting formation 115 travels through backing material 107.

To cut the tuft, tufting needle performs a tufting stroke wherein the cutting edge 115 is directed to cut by axial movement of the tufting needle 100 along the shaft axis 125 towards the first end 123. At the same time, tension is placed on filament 111 preventing further extension of the tuft 113′ through the backing material. The tension allows cutting edge 115 to drive through the tuft thereby cutting it.

In some embodiments, cutting edge 115 is axially distal from first end 123 relative to other portions of opening 117. That is, cutting edge 115 is recessed away from the tapered formation apex relative to other portions of the lumen opening 117. This recess allows needle 100 to trap filament 111 on cutting edge 115 such that if a cutting stroke is performed, filament 111 will be in contact with cutting edge 115 rather than some other portion of opening 117. For example, cutting edge may be located at the apex of a ‘V’ notch in opening 117 as illustrated in FIG. 1 .

In some embodiments, opening 117 comprises guide portions 129 configured to guide filament 111 to cutting edge 115. For example, in the ‘V’ notch configuration described above, the diagonal sides of the ‘V’ would guide filament 111 to cutting edge 115 located at the apex of the ‘V’ when tension is placed on filament 111. Similarly, a ‘U’ shaped notch could be used to achieve a similar effect where the vertical side of the ‘U’ would act to guide a tensioned filament to cutting edge 115 located on the base portion of the ‘U.’

In some embodiments, the tapered formation is a bevel surface 119 leading to a needle point 121 at a leading end, referred to as the first end 123 of needle 100. Cutting edge 115 is located on the heel of the bevel. In this configuration, cutting edge 115 is located on the most axially distant edge of opening 117 from point 121. In this case, portions other than the cutting edge 115 of opening 117 act as guide portions, guiding tensioned filament 111 toward cutting edge 115. In yet other embodiments, cutting edge 115 is located in a ‘V’ notch or ‘U’ notch at the heel of the bevel, thereby further enhancing the guide properties of guide portions of opening 117.

It will be appreciated that, for a given filament gauge, the appropriate gauge for needle 100 is smaller than the gauge of a traditional tufting needle. The smaller gauge is the result of needle 100 not having to accommodate a separate cutting blade within the needle lumen, as traditional tufting needles do. The lower external circumference of needle 100 results in a lower penetrating force for needle 100 to penetrate backing material 107. Consequently, the power requirements for tufting with needle 100 are reduced in comparison to a traditional tufting needle. Furthermore, there is a reduction in required size to the actuator which reciprocates needle 100. The reduced size and power requirements allow for the construction of smaller, battery-powered tufting devices which are capable of moving and tufting faster than traditional tufting devices.

A tufting needle causes a distortion in a backing material when penetrating it. This distortion increases with the size of the external circumference of the tufting needle. Accordingly, the smaller gauge of needle 100 reduces the distortion of the backing material during each penetration. The final tufted fabric is produced by multiple needle penetrations such that reduced distortion of each individual needle penetration is cumulative and leads to an overall reduction of distortion of the final tufted fabric.

In some embodiments, shaft 101 comprises one or more engagement surfaces 133 as shown in the cross-section of shaft 101 in FIG. 1C, which is taken along axis A-A of FIG. 1A. Engagement surfaces 133 engage with a rotating actuator 134 described in greater detail below with reference to FIGS. 4A and 4B.

In some embodiments, the engagement surfaces 133 include first engagement surfaces 135 as part of a key system 137, wherein the key system 137 rotates the tufting needle 100 with corresponding rotation of the rotating actuator 134. In some embodiments, key system 137 is an axially slidable key to enable, at least in part, the tufting needle 100 to move axially along the shaft axis 125. For example, engagement surfaces 135 may be one or more planar surfaces proximal to the second end 127 of the shaft and parallel to the shaft axis 125. It will be appreciated that many other configurations for the engagement surfaces are possible. For example, surface formations which extend radially from shaft 101 and extend axially along shaft 101 could also define a suitable key system 137 with a rotating actuator 134.

In some embodiments, needle 100 comprises second engagement surfaces 138 as part of a reciprocating system 139, wherein the reciprocating system 139 selectively moves the tufting needle 100 along the shaft axis 125. That is, engagement surfaces 138 engage with a linear actuator to allow reciprocation of needle 100 while engagement surfaces 133 engage with a rotating actuator 134 to allow rotation of needle 100. As with the first engagement surfaces, it will be appreciated that second engagement surfaces 138 can be configured in many different ways. For example, in one embodiment, second engagement surfaces 138 comprise one or more collars 141 or grooves 143 on shaft 101 to engage reciprocating system 139. In some embodiments, second engagements surface 138 allow needle 100 to be rotatably captured by linear actuator 139. That is, needle 100 is able to rotate within and relative to linear actuator 139 but is not able to slide axially relative to actuator 139. In other embodiments, moving core 157 of actuator 139 rotates with needle 100.

It will be appreciated that backing material 107 can be selected from a variety of different backing materials. For example, in FIG. 2 backing material 107 is illustrated as a woven fabric. In this case, passage 105 is a distortion in the weave which is resiliently biased back into the undistorted weave when needle 100 is retracted. That is, individual strands in backing material 107 are not severed during penetration.

Backing material may also be a sheet of resiliently biased material such as a rubber or plastic sheet. In this case, passage 105 is the result of needle 100 severing the backing material 107. Resilient bias in backing 107 is sufficient to substantially close passage 105 after needle 100 is retracted.

Tufting Gun

Overview

Existing electro-mechanical tufting guns are relatively large and heavy, requiring physical strength to operate thereby limiting their use to physically stronger users. Even among these users, fatigue limits productivity and can effect quality. Smaller, drill type tufting guns ae made for physically weaker users, but these are limited to smaller gauge filaments, or yarn in the case of carpet making.

In addition tufting gun functions, such as pile type height are mechanically determined and require setting by an operator. This is time consuming and can be complex. Furthermore, physical dexterity is required to rotate the needle via a lever arm to match the tufting speed.

Tufting heads using electro-mechanical tufting guns in tufting robots are unable to change pile type or pile height electronically. The tufting robot needs to be stopped to make changes mechanically.

An electronically controlled electro-mechanical tufting gun, for selectively tufting either cut pile or loop pile of a selectable pile height, is disclosed.

FIG. 3 shows the cross section of an electro-mechanical tufting gun 300 with the tufting needle 100 in extended position (top) and retracted position (bottom). A filament feed system 15 comprises the yarn feed motor 16 which drives a driven filament feed roller 17 pinching the filament 111 between itself and a filament feed reaction roller 18. This filament feed system feeds a filament into tufting needle 100 and through a passage 105 to be created in the backing material by the penetration of needle 100. Tufting gun 300 is controlled by an electronic control system 302 which stores pile height values and controls all the functions and operations of the tufting gun, including filament cutting, tufting needle reciprocation, tufting needle rotation, filament feeding, and backing displacement.

The needle 100 is connected to a moving core 139 of a linear actuator and is linearly guided by hollow rotation shaft 9 of a rotating actuator 134. The linear actuator 139, which reciprocates the needle 100 between the extended position (top) and retracted position (bottom), comprises a moving core 13 and the matching stator 14 which is fixed in place in the lower housing 19. This is described in greater detail below.

Needle Rotator

The needle rotator system consists of a hollow rotation shaft 9 of rotating actuator 134 connected by key system 137 to the needle 100. On a signal from a tufting gun controller, the needle rotator system 134 rotates hollow rotation shaft 9, which, through key system 137, causes rotation of needle 100. In use, needle rotation only occurs after the needle is totally withdrawn from contact with the backing material 117. Accordingly, in some embodiments, first engagement surfaces 133 of needle 100 may only be formed at proximal first end 123 of needle 100. It will be appreciated that needle rotator 134 can take many forms. For example, in FIG. 3 it is illustrated as an electric motor having a hollow motor shaft configured to receive and rotate a tufting needle 100.

In some embodiments, such as the cross sectional view of hollow motor shaft 134 shown in FIG. 5 , the hollow motor shaft 134 comprises hollow core 153 and engagement surfaces 145 to engage with first engagement surfaces 133 of needle 100. The engagement surfaces 145 are part of an axially slidable key system 137 to allow the needle to move axially in the motor shaft 134. This allows rotating actuator 134 to remain fixed in space as needle 100 reciprocates through shaft 9 while still providing the capability to rotate needle 100.

In operation, the needle, carried forward by the linear needle reciprocator 139, penetrates backing material with the yarn being fed down the needle-blade's hollow tube. The friction between yarn and backing holds the yarn at one end and the body of the yarn is carried forward through the hole by the v groove in the needle-blade. At the desired pile height, the advanced the backing material, through the hole it has created, into the backing material. At the desired pile height, the linear needle reciprocator reverses direction to withdraw the needle-blade from the backing. As the needle-blade is withdrawn a tuft is formed. As soon as the needle-blade has completely disengaged from the backing, the direct needle rotator rotates the needle into the angular position required for creating the stitch leading to the next tuft.

The yarn feed is electronically controlled and is synchronized to the needle reciprocation. Selection of cut pile or loop pile is electronically controlled. For cut pile or yarn cutting, the feed system 15 is used as a brake, being electronically applied at the appropriate part of the tufting cycle. The tufting speed may be set at a constant value or controlled by the operator through a trigger, as is currently done. The pile type and pile height are set electronically with storage of a number of different sets of values. The stroke of the linear needle reciprocator determines the pile height and that stroke is electronically controlled and infinitely variable. Needle rotation is electronically controlled to occur in the appropriate part of the tufting cycle with the rotation angle set through a trigger, like a computer game.

In some implementations, the embodiment may provide significant improvements over existing tufting guns. For example:

a. settings for pile type and pile height are electronic and instantaneous,

b. tufting gun has fewer parts, is less complex and is easier to operate and maintain,

c. size reduction of 40% to 50%,

d. weight savings in the tufting gun are in the range of 30% to 50%,

e. costs savings in the tufting gun are in the range of 25% to 30%,

The benefits of the embodiment may be increased productivity, lower cost of ownership, easier operation, and reduced operator stress.

One embodiment of the disclosure may be a hand gun for two handed operation with one trigger for speed control and the other for needle rotation. Another embodiment may have one-handed operation with set speed control and trigger operation of needle rotation. The electronic controls for the tufting gun may be through push buttons or keyboards. Another embodiment may utilize voice control to operate the tufting gun.

As noted in U.S. Pat. No. 5,829,372 (Aubourg et al) needle rotation occupies 30%-40% the tufting cycle and so it is an important performance issue. As mentioned, existing tufting guns indirectly rotate the needle by rotating the presser foot to which the tufting needle itself is attached. In hand guns, a lever arm is used to rotate the presser foot. Tufting guns mounted in tufting heads, as used in robot tufting, indirectly rotate the tufting needle in one of two ways. Either the whole tufting head is rotated, or, as disclosed in U.S. Pat. No. 7,218,987 B2 (Mile et al), it is done by “rotating the presser foot in an inter-engaging formation with the needle.”

This embodiment provides a simple and cost effective means of direct needle rotation. It comprises a needle rotator keyed into an electric rotation motor. The rotator is a hollow shaft with a female socket shaped central hole matching the non-circular external male shape of a tufting needle-blade. Rotating the rotator directly rotates the needle blade. The needle-blade is able to reciprocate longitudinally within the rotator, independently of any rotating movement, guided by the shape of the rotator hole. The bottom surface of the rotator acts as a presser foot for locally constraining the backing material during withdrawal of the needle. The embodiment may mitigate some of the problems of existing tufting guns and tufting heads by the following means:

a. It directly rotates the tufting needle through a single component, the rotator, directly driven by a motor, reducing the complexity, mass, rotational inertia, size, power and cost of existing needle rotation mechanisms by several orders of magnitude.

b. It enables the tufting needle to be reciprocated independently of rotation.

c. It eliminates a separate presser foot.

d. It reduces the power required to rotate the needle while increasing the speed of needle rotation with a consequent improvement in tufting performance.

e. The reduction in size and weight of tufting guns and tufting heads results in lighter, faster, and less expensive XY movement systems in tufting robots.

The benefits of this embodiment may include the potential to reduce the size and cost of tufting guns by 25%, reduce average tufting cycle time by around 10%, and reduce the cost of tufting robots by at least 10%.

In other embodiments, motor shaft 9 is not hollow and engages with needle 100 on an external surface of shaft 9 such as through a gearing system.

Presser Foot

Formation of tufts relies on the presser foot exerting sufficient pressure on the backing material to hold it from being drawn upwards by the withdrawal of the tufting needle. Insufficient pressure by the tufting foot can result in poor and irregular tuft formation. Excessive pressure causes greater deflection of the backing material which can lead to tearing of the backing material in low tensile strength backing materials. Hand tufting quality is determined by the consistency with which the operator applies force through the presser foot against the backing. The problems with this are:

a. an operator relies on subjective feedback, tactile and visual, to regulate the force exerted.

b. hand tufting is physically demanding and tiredness can affect the ability to regulate the force being exerted.

c. tufting guns can reciprocate the tufting needle without being physically engaged with a backing, which represents an operator safety problem. Accidental pressing of the tufting gun trigger can be dangerous.

A presser foot 10 is formed on the bottom surface of the hollow rotation shaft 9 and this presser foot locally depresses the backing material. In some embodiments, presser foot 10, also referred to as a pressing formation 147 comprises a high friction surface 149 for engaging the filament 111 and backing material 107.

In some embodiments, rotator system 134 further comprises a pressure sensor 151 to measure a pressure between pressing formation 147 and backing material 117.

This embodiment measures the localized force exerted by a tufting against a backing material by measuring the pressure exerted on a presser foot. The pressure is then converted by an electronic controller into a signal which may be used for objective force indication or tufting gun control or both. This provides:

a. A signal indicating that the force being exerted is within the acceptable range for good quality tufting. This signal may be visual, such as a light, or audible, or tactile.

b. An electronic control signal to prevent the tufting gun operating if it is not in contact with a backing.

One means of the embodiment may be a pressure sensitive material attached to the presser area, such as a piezo electric material, that provides an electrical signal proportional to the pressure exerted against the backing material. Another means may be a spring loaded surface of the tufting gun acting as a presser area and an electrical sensor indicating when the threshold pressure has been achieved.

Linear Actuator

Existing tufting guns use a mechanical crank, connecting rod and slider block mechanism to linearly reciprocate a tufting needle. This mechanism has a number of limitations and problems.

a. It is quite complex with numerous components with several wearing parts

b. It requires balancing and is limited in its maximum operating speed

c. It has a fixed stroke which can only be altered by mechanical adjustment of the mechanism.

d. The linear reciprocation is sinusoidal with a fixed, non-adjustable velocity profile.

The top diagram of FIG. 3 shows the tufting needle 100, driven by the linear actuator's moving core 139 to an extended position where it would penetrate the backing material 117 to create a passage 105 through which the filament 111 is fed by the V groove 5 in the tufting needle 100. The travel of the needle 100 is electronically controlled with the stroke length selectable anywhere between top dead center, as in bottom diagram of FIG. 3 , and bottom dead center at end of the linear actuator's stroke as in bottom diagram of FIG. 3 .

The linear actuator, also referred to as a linear needle reciprocator, reciprocates needle 100 in a linear mode. The linear actuator 139 comprises a moving core 157 to which a tufting needle 100 is attached. Core 157 comprises an aperture 159 to capture needle 100 by engaging with second engagements surface 138 of needle 100. Aperture 159 engages collars 141 to effect linear movement of needle 100 but allow needle 100 to rotate on axis 125.

Linear actuator 139 further comprises an electric motor to power the moving core 157 in reversible linear motion and reciprocate the attached tufting needle, a linear position sensing means, and an electronic control system to control the direction, stroke, linear speed, reciprocation frequency, and reciprocation waveform of the moving core.

Linear actuator 139 provides a simpler, smaller, lighter, more controllable and less expensive means of tufting needle reciprocation than existing methods.

The electric linear actuator may be a lead screw powered by an electric motor, a linear electric motor, a solenoid, a voice coil motor or any similar type of linear actuator. Where a voice coil motor is used the moving core can be either the magnet or the electric coil.

Pneumatic Feed

Air Jet Tufting Gun

A nozzle is a relatively simple device used to direct the flow of compressed air as it leaves the outlet of the nozzle. In the case of pneumatic tufting guns, the nozzle is an annular opening around a tufting needle which contains a filament that is to be inserted as a tuft. As the compressed air leaves the annular orifice it entrains the filament imparting it with a velocity that creates kinetic energy equal to the filament mass times the square of the velocity. This kinetic energy drives the filament and creates the thrust which drives the filament through the opening created in the backing material by the tufting needle. Nozzles in existing pneumatic tufting guns feed the air in a jet stream along a parallel or converging path to the nozzle exit point where in entrains the filament. At the point of exit from the nozzle, the air flow is incompressible and its velocity is subsonic such that the sudden enlargement of the area around the jet stream actually reduces the exit velocity. This reduction in jet velocity reduces the force driving the yarn within a relatively short distance from the nozzle exit.

Pneumatic tufting guns are relatively large and heavy, requiring physical strength to operate. Extended use of these heavy hand guns is physically tiring which limits productivity and can affect quality. Smaller drill type tufting guns exist, but are limited to use with smaller gauge filaments, or yarn in the special case of carpet manufacture.

Additionally, tufting gun functions, such as pile type height are mechanically determined and require setting by an operator. This is time consuming and can be complex. Furthermore, rotation of the needle via a lever arm to match the tufting speed requires physical dexterity.

Further, in existing pneumatic tufting guns, the stream of air is created by a convergent nozzle which creates subsonic incompressible gas flow. As this stream of air leaves the nozzle it becomes turbulent and loses velocity thereby reducing the speed and force propelling the filament through the tufting needle. The inefficiency of the air stream limits the speed of tufting and the force required to push the yarn through the backing and the adjacent tufts.

In addition, the reduced speed and force of the air stream necessitates the use of long tufting needles to protect the injected yarn from entanglement with surrounding tufts in the backing. Therefore, different lengths of tufting needles are required according to the pile height.

Yarn robbing may also occur in existing pneumatic tufting guns. This occurs when a new tuft is inserted in the backing and the yarn insertion force is greater than the yarn frictional holding force from the previous tuft. The yarn is then drawn from the previous tuft, thereby changing the effective pile height of tufts to reduce tufting quality.

The velocity V, measured in m/s, of a gas stream produced by a pneumatic feed is given by:

$V = \sqrt{\frac{2P_{d}}{\rho_{f}}}$

In this equation, Pa is the dynamic pressure in pascals (Pa) that is the difference in pressure inside the nozzle at after the outlet, and ρ_(f) is the density of the gas (assumed to be air) in kg/m³.

In a convergent and divergent (CD) nozzle, the air leaves a chamber and converges down to the minimum area, or throat, of the nozzle. The throat size is chosen to choke the flow and set the mass flow rate of air through the system with the velocity of the flow in the throat being sonic with a Mach number around one. Downstream of the throat, the geometry diverges and the flow is expanded to a supersonic Mach number that depends on the area ratio of the exit to the throat. The expansion of a supersonic flow causes the static pressure and temperature to decrease from the throat to the exit, so the amount of the expansion also determines the exit pressure and temperature. The exit temperature determines the exit Mach number which determines the exit velocity. The exit velocity, pressure, and mass flow through the nozzle determines the amount of thrust produced by the nozzle—doubling the velocity quadruples the thrust on the filament.

Air jets generate an airstream of supersonic compressible air with a fixed mass flow rate set by choking the flow at the minimum area of a convergent and divergent nozzle. This results in reduction of air density and a corresponding increase in velocity as determined by the formula above. For a given inlet air pressure, the rate of increase in velocity is defined by the air density reduction as the air is compressed.

Air jets have previously been used in in weaving and other textile processes for the pneumatic insertion of weft filaments in weaving machines, known as air jet weaving. In weaving the weft filaments are entrained in a supersonic stream of compressible air to provide the thrust to carry it in a straight line over distances of 3 to 4 meters. Air jets have not traditionally been used in tufting. An embodiment of a tufting gun utilizing an air jet is described below with reference to FIGS. 4A, 4B, 4C, and 6 .

A cross section of an air jet tufting gun 300′ is shown in FIGS. 4A and 4B. FIG. 4A shows the tufting needle 100 at bottom dead center, end of stroke, after needle penetration. FIG. 4B shows the tufting needle 100 at top dead center before penetration of the backing material. The tufting needle 100 reciprocates between these positions and, during normal tufting operations, does not stop at any point between.

The filament feed system 15 together with the air jet nozzle 20 are located in the upper housing of the tufting gun 300′. The linear actuator stator 14 is mounted in the bottom housing 22 whose bottom surface forms a non-rotating presser foot 10. The needle carriage 23, attached to the moving core of the linear actuator 139, reciprocates axially in a guided manner within the bottom housing 22 carrying with it the needle 100, the needle rotation system, and the yarn cutting system.

In some embodiments, the presser foot 10 is formed on the bottom surface of the hollow rotation shaft 134 as described above.

The needle rotation motor 134 is fixed in place in a needle carriage 23 and is directly connected to the tufting needle 100 by key system 137.

In embodiments utilizing a traditional tufting needle in place of needle 100 described above, needle rotation only occurs after the needle is totally withdrawn from contact with the backing material (not shown). The filament cutting system sits in the needle carriage 30 above the needle rotation system. It comprises an eccentric blade 28 rotated by the cutting blade motor 29 to sweep over the top end of the tufting needle blade to cut the yarn.

The backing material is deflected by the presser foot 10 when the tufting gun is lowered to start tufting. A signal from the controller starts the linear actuator 139 moving the needle 100 toward the backing material. During the movement, the tufting needle 100 penetrates the backing material when extended, as shown in FIG. 4A. The filament feed system 15, operated by the controller, feeds the amount of filament that will be required to form the next tuft and then stops, to act as a brake on the filament and preventing further filament from entering gun 300′.

FIG. 4A shows the needle 100 at the bottom of its travel where needle 100 would completely penetrated the backing material. The presser foot 10, which in some embodiments has a high friction surface 149, presses the filament 111 in the stitch 155 (see FIG. 2B) from the previous tuft against the backing material 117. This pressure creates a horizontal friction force to resist the insertion force exerted on the filament during the formation of the next tuft. When the tufting needle 100 reached its end of stroke, a signal from the controller starts the flow of compressed air through the air jet nozzle 20. The stream of air carries the full amount of filament for the tuft through filament lumen 109 in needle 100. The braking system mentioned above prevents excess filament from being pulled though the backing material and thereby allows the tuft height to be determined. It will be appreciated that by using the compressed air to force the filament through needle 100, and therefore backing material 117, that needle 100 does not have to extend to the full height of the tuft as the needle stroke is no longer determining the tuft height.

A signal from the controller initiates a reversal of direction of the needle 100, withdrawing the needle from the backing material. As the needle is withdrawn, if cut pile has been specified in the design, a signal from the controller initiates filament cutting. If the tufting needle used is needle 100 described above, then the filament cutting is effected by performing a cutting stroke by moving further through the backing material as described above.

The filament feed system 15 together with the air jet nozzle 20 are located in the upper housing of the tufting gun 300′. A stator 14 of linear actuator 139 is mounted in the bottom housing 22 whose bottom surface forms a non-rotating presser foot 10. The needle carriage 23, attached to the moving core of the linear actuator 139, reciprocates axially in a guided manner within the bottom housing 22 carrying with it the needle 100, the needle rotation system, and the yarn cutting system.

In some embodiments, presser foot 10 is formed on the bottom surface of the hollow rotation shaft 134 as described above.

The needle rotation motor 134 is fixed in place in a needle carriage 23 and is directly connected to the tufting needle 100 by key system 137. Needle rotation only occurs after the needle 100 is totally withdrawn from contact with the backing material (not shown). The filament cutting system sits in the needle carriage 30 above the needle rotation system. It comprises an eccentric blade 28 rotated by the cutting blade motor 29 to sweep over the top end of the tufting needle blade to cut the yarn.

The backing material is deflected by the presser foot 10 when the tufting gun is lowered to start tufting. A signal from the controller starts the linear actuator 139 moving the needle 100 toward the backing material. During the movement, the tufting needle 100 penetrates the backing material when extended, as shown in FIG. 4A. The filament feed system 15, operated by the controller, feeds the amount of filament that will be required to form the next tuft and then stops, acting as a brake on the filament and preventing further filament from entering gun 300′.

Air jet tufting gun 300′ can selectively tuft either cut pile or loop pile of a selectable pile height.

As mentioned, tufting gun 300′ utilizes a convergent and divergent air jet nozzle 20 to create a supersonic stream of air as described below. This system is positioned between the filament, or yarn, the feed system, and the filament inlet. The bottom surface of the housing provides a non-rotating presser foot against the backing material. The motor of the direct needle rotator is keyed into the needle-blade with the whole motor/needle blade assembly attached to and moving with the linear needle reciprocator. The cutting system is also attached to the linear needle reciprocator and is positioned above the top of the needle-blade. The cutting blades are selectively operated to cut the yarn and create a selected tuft length. The needle-blade includes a roughened disk surface which, at end of stroke, sandwiches the previous tuft against the backing. This disk, called a tuft lock, prevents yarn robbing to provide better quality tufting.

FIG. 4C illustrates an expanded view of convergent and divergent nozzle 20. Nozzle 20 comprises a chamber 402 with side walls 404 and an exit aperture 406. Side walls 404 comprise a converging wall section 408 and a diverging wall section 410. Compressed gas enters chamber 402 through inlet 21. Convergent walls 408 increase the kinetic energy of the gas, at the expense of pressure, as the gas moves through nozzle throat 412. The gas further accelerates to supersonic speeds as it passes divergent section 410 before exiting exit aperture 406. It will be appreciated that the relative dimensions of nozzle 20 are determined based on the requirements of the intended application.

The supersonic airstream generated by convergent and divergent nozzle 20 flows at over twice the velocity of airstreams used in current pneumatic tufting guns. The filament insertion force increases quadratically with airstream velocity and therefore the supersonic airstream created by tufting gun 300′ is more efficient and uses less air/compressed gas when compared to traditional pneumatic tufting guns.

A further advantage of tufting gun 300′ is that the pile type and height are set electronically and can therefore change dynamically during operation, whereas existing tufting guns require mechanical settings and therefore for the gun to stop tufting. Tufting gun 300′ is therefore easier to operate. Furthermore, tufting gun 300′ contains fewer parts thereby reducing maintenance. For example, tufting gun 300′ has a size reduction of approximately 30% to 40%, a weight reduction of around 30% to 50%, and a manufacturing cost reduction of 25% to 30%.

Electro-Mechanical Tufting Gun

FIG. 6 shows a cross section of a tufting gun combining an electro-mechanical tufting mechanism with an air jet feed system. A convergent and divergent air jet nozzle 20 is fixed in the upper housing 15. On a signal from the tufting gun controller compressed air supplied through the air inlet 21 to send a supersonic stream of compressed air to carry the yarn through the needle 100.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. 

1. A tufting needle comprising: a shaft having: a tapered formation configured to penetrate and open a passage in a resilient backing material from reciprocating movement of the tufting needle along a shaft axis of the shaft; and one or more engagement surfaces to engage with a rotating actuator, wherein the rotating actuator rotates the tufting needle around the shaft axis of the shaft; a filament lumen that leads to an opening proximal to the tapered formation, to guide a filament through the passage to create a tuft at the resilient backing material; and a cutting edge located at the opening of the filament lumen to cut the filament.
 2. A tufting needle according to claim 1, wherein the shaft extends from a first end proximal to the tapered formation to an opposite second end, and at least a portion of the filament lumen is coaxial with the shaft axis.
 3. A tufting needle according to claim 2, wherein the tapered formation comprises a bevel surface leading from a needle point at the first end of the shaft.
 4. A tufting needle according to claim 2, wherein the cutting edge is, relative to other portions of the opening, axially distal from the first end, wherein the cutting edge is directed to cut by axial movement of the tufting needle along the shaft axis towards the first end.
 5. A tufting needle according to claim 1, wherein the opening comprises guide portions configured to guide the filament to the cutting edge.
 6. A tufting needle according to claim 5, wherein at least part of the guide portions is substantially V shaped to channel the filament to the cutting edge.
 7. A tufting needle according to claim 5, wherein at least part of the guide portions is substantially U shaped to channel the filament to the cutting edge.
 8. A tufting needle according to claim 5, wherein at least part of the guide portions includes at least part of the cutting edge.
 9. (canceled)
 10. A tufting needle according to claim 1, wherein the one or more engagement surfaces include one or more first engagement surfaces as part of a key system, wherein the key system rotates the tufting needle with corresponding rotation of the rotating actuator.
 11. A tufting needle according to claim 10, wherein the key system is an axially slidable key to enable, at least in part, the tufting needle to move axially along the shaft axis.
 12. A tufting needle according to claim 10 wherein the one or more first engagement surfaces are one or more planar surfaces proximal to the second end of the shaft and parallel to the shaft axis.
 13. A tufting needle according to claim 1, wherein the one or more engagement surfaces include a second engagement surface as part of a reciprocating system, wherein the reciprocating system selectively moves the tufting needle along the shaft axis.
 14. A tufting needle according to claim 13 wherein the second engagement surface is formed from one or more collars or grooves on the shaft.
 15. A tufting needle according to claim 13 wherein the second engagement surface is rotatably captured by the reciprocating system.
 16. The tufting needle according to claim 1 wherein the resilient backing material is a woven fabric.
 17. The tufting needle according to claim 1 wherein the filament is yarn.
 18. A needle rotator comprising an electric motor having a hollow motor shaft configured to receive and rotate a tufting needle according to claim
 1. 19. The needle rotator according to claim 18 wherein the hollow motor shaft comprises one or more engagement surfaces to engage with the needle.
 20. The needle rotator according to claim 19 wherein the one or more engagement surfaces are part of an axially slidable key system to allow the needle to move axially in the hollow motor shaft.
 21. The needle rotator according to claim 20 wherein the one or more engagement surfaces are planar surfaces parallel to the motor shaft axis.
 22. The needle rotator according to claim 18 further comprising a pressing formation on a distal end of the hollow motor shaft.
 23. The needle rotator according to claim 22 wherein the pressing formation comprises a high friction surface for engaging a filament and a backing material.
 24. The needle rotator according to claim 22 further comprising a pressure sensor to measure a pressure between the pressing formation and a backing material.
 25. A linear actuator comprising a stator and a moving core, wherein the moving core comprises an aperture to rotatably capture, by a second engagement surface, a tufting needle according to claim
 13. 26. The linear actuator of claim 25 wherein the second engagement surface is formed from one or more collars or grooves on the shaft of the tufting needle.
 27. A tufting gun comprising: a filament port to introduce a filament into the tufting gun; a convergent and divergent jet nozzle formed symmetrically about the filament port and configured to generate a supersonic stream of compressed gas to entrain the filament to a tufting needle according to claim 1; and a needle rotator comprising an electric motor having a hollow motor shaft configured to receive and rotate the tufting needle according to claim
 1. 28-29. (canceled)
 30. The tufting gun of claim 27 further comprising a linear actuator, wherein the linear actuator comprises: a stator and a moving core, wherein the moving core comprises an aperture to rotatably capture, by a second engagement surface, the tufting needle according to claim 1, wherein the one or more engagement surfaces of the shaft of the tufting needle include the second engagement surface as part of a reciprocating system, wherein the reciprocating system selectively moves the tufting needle along the shaft axis. 